Assay validation and determination of the reference interval for symmetric dimethylarginine in healthy rabbits

Abstract

BackgroundChronic kidney disease (CKD) is common in older rabbits. The renal biomarkers blood urea and creatinine can be insensitive as indicators of renal disease in rabbits. Symmetric dimethylarginine (SDMA) has been shown to be an earlier and more sensitive biomarker for the assessment of glomerular filtration rate and the evaluation of CKD in several animal species. An immunoassay for SDMA has been validated in a number of species. The purpose of this study was to validate the SDMA immunoassay for rabbit serum and plasma and to determine the normal rabbit reference interval (RI) for SDMA. MethodsClinically healthy rabbits (n=167) between 5 months and 8 years of age, of any breed or sex, participated in the study. Heparinized plasma or serum was collected for clinical chemistry and used for assay validation. Analytical validation of the SDMA immunoassay for rabbit serum and plasma was performed and included assessment of assay accuracy, precision, analytical sensitivity, linearity, interference testing, and plasma/ serum bias. The SDMA reference interval (RI) was determined. ResultsThe SDMA immunoassay met all set quality requirements assessed in analytical validation. The RI for SDMA was determined to be between 4 - 18 µg/dL. Conclusions and clinical relevanceThe SDMA immunoassay demonstrated acceptable performance in both rabbit serum and heparinized plasma as determined by the validation criteria. Although the utility of SDMA as a biomarker of renal disease in rabbits has not been determined, validation of the SDMA immunoassay should facilitate evaluation of SDMA levels in rabbits with confirmed renal disease.